A spacer double patterning method is known as a method of efficiently forming a fine pattern with a high degree of accuracy (for example, see Patent Document 1). In the spacer double patterning method, for example, after depositing a predetermined film on a semiconductor wafer on which a film to be etched and a line-patterned layer is already deposited, the line-patterned layer is removed and the predetermined film other than side walls of the line-patterned layer is removed by an etching. The film to be etched is etched by using the remaining predetermined film as a mask.